Synthesis and in vivo evaluation of 3-[C-11]methyl-(3-methoxy-naphthalen)-2-yl-(1-benzyl-piperidin)-4-yl-acetate (SB-235753), as a putative dopamine D-4 receptors antagonist for PET
M. Matarrese et al., Synthesis and in vivo evaluation of 3-[C-11]methyl-(3-methoxy-naphthalen)-2-yl-(1-benzyl-piperidin)-4-yl-acetate (SB-235753), as a putative dopamine D-4 receptors antagonist for PET, J LABEL C R, 43(4), 2000, pp. 359-374
(3-Methoxy-naphthalen)-2-yl- (1-benzyl-piperidin) 4-yl-acetate (SB-235753)
was labelled with C-11 (t(1/2) = 20.4 min) as a putative radioligand for th
e non-invasive assessment of Dopamine D-4 receptors in vivo with positron e
mission tomography (PET).
The precursor for the radiosynthesis 3-hydroxynaphthyl-2-[(N-benzyl)piperid
yl]-acetate hydrochloride was prepared by a four-step synthesis starting fr
om ethyl-4-pyridyl acetate. The radiolabelling consisted of methylation wit
h [C-11]methyltriflate in dimethylformamide in the presence of potassium hy
droxide. [C-11]SB-235753, was synthesised in 30 min with a radiochemical yi
eld of 10 +/- 5% (EOS, non-decay corrected) with 99% radiochemical purity a
nd specific radioactivity of 10 +/- 3 Ci/mu mol.
Biodistribution studies in rats with [C-11]SB-235753 showed the uniform dis
tribution of the tracer within different areas of the murine brain. At 30 m
in after injection 99% of the radioligand in plasma and 100% in cerebellum
was metabolised. These findings-suggest that [C-11]SB-235753 can not be a s
uitable tracer for dopamine D-4 receptor studies with PET.